Eraser for mechanical pencils



Aug.i25, 1942. J. P. LYNN ERASER FOR MECHANICAL PENCILS Original FiledJune 15, 1938 I Y II;IVEI\JTOIR. Lia/2121 477272,

BY M Patented Aug. 25, 1942 UNETED STTE ERASER FOB MECHANICAL PENCILSJohn P. Lynn, Chicago, 111., assignor to Dur-O- Lite Pencil Company,Melrose Park, 111., a corporation of Delaware 7 Claims.

This invention relates to novel eraser constructions which are providedwith elongated erasers capable of being propelled and retracted withineraser holding containers and which bodily may be housed within andremoved from the upper end of the pencil barrel, as desired, thisapplication being a division of application Serial No. 213,754, filedJune l5, 1938.

Among the objects of the present invention is to provide an eraserassembly which is capable of being bodily removed from the upper end ofa pencil and reinserted therein from either end so that a closing cap isprovided for the end of the pencil in one position or the exposed eraseris provided in the other position.

Another object of the invention is to provide an eraser assembly whichis utilized in combination with the step-by-step type of lead propellingmechanism and in which the eraser assembly serves as the means at thehead end of the pencil for exerting the pumping action on the leadpropelling mechanism.

The invention further relates to improved eraser propelling andretracting mechanism whereby a very efficient construction and opera- 2tion result while at the same time providing a simple and inexpensivearrangement of parts.

Other objects, features, capabilities and advantages are comprehended bythe invention, as will later appear and as are inherently possessedthereby.

Referring to the drawing Figure l is a longitudinal cross-sectional Viewof an eraser assembly constructed in accordance with this invention;

Figure 2 is a cross-sectional view taken on the line 2-2 of Figure 1 andlooking in the direction of the arrows;

Figure 3 is an elevational view, partly in crosssection, of the eraserassembly shown in Figure 1 of the drawings;

Figure 4 is a side elevational View of the threaded stem and head pieceutilized in the eraser assembly shown in Figure 3;

Figure 5 is a side elevational view of the eraser and cap memberutilized in the assembly shown in Figure 3; and

Figure 6 is a cross-sectional View taken on the line 6-5 through theeraser assembly of Figure 3 and looking in the direction of the arrows.

Referring now more in detail to the drawing, an eraser assembly 2selected to illustrate the invention is shown in connection with apencil having a body 4 of substantially cylindrical shape throughout aportion of its length, the

same having an opening at one end and being provided with a taperedportion forming a tip 5 at its other end. Enclosed within said body 4 isa step-by-step type lead propelling or feeding mechanism referred togenerally by the reference numeral 8, and including a lead magazine 10connected to and being adapted for operation of the lead propellingmechanism 8, the said magazine 10 terminating short of the upper openend of the body 4, as at 12.

The eraser mechanism to which this invention is particularly directed iscomposed of a threaded screw I which is permanently attached to a head16. The head is preferably drilled and inserted over the screw member,with the screw end enlarged, as at 18, in the opening at the top of thehead so as to hold the members in fixed relationship. The head isprovided with an annular groove 20 and a flange 22 preferably having aknurled outer edge.

Surrounding the threaded member 14 is a tubular body portion or housingelement 24 having its upper end reduced, as at 26, for engaging thatportion of the head below the flange 22. The fit at this point is soadjusted that the housing element 24 may turn relative to the head whendesired. The tubular body portion 24 has indented portions 28 which fitwithin the groove 28, whereby the housing element 24 is held againstaxial displacement, while at the same time being free to rotate on thehead.

Preferably a cap member or housing element 38 having a domed end 32 isfitted over the knurled flange 22 and fixedly attached thereto. Thedepending portion 34 of the housing element 38 is of such diameter thatit forms a continuation of the cylindrical surface of the tubular bodyportion or housing element 24. It will thus be apparent that the housingelement 24 may be held in the fingers of one hand while the housingelement is turned by the other hand, and that during such operationthere will be a relative turning movement between the tubular body orhousing element 2 and the screw 14!.

Disposed within the tubular body or housing element 24 is an elongatedcylindrically-shaped eraser 3t having a central opening 38 therein. Thiseraser has one end fitted in a cap 4-3 which has a centralscrew-threaded opening 42 at the top for engagement with the screw 14.The cap further has spring fingers 44 for tightly gripping the eraser,whereby the eraser is held against axial and rotational movementrelative to the cap member. Furthermore, the spring fingers M, by virtueof their construction, are caused to project slightly outwardly from theexterior cylindrical surface of the cap member 40, whereby they providea slight frictional drag on the interior of the cylindrical body orhousing element 24.

The construction is such that although the eraser is not positively heldagainst rotation in the housing element 24, it will, nevertheless,resist such rotation due to the frictional action of the fingers 44,whereby the turning of the housing element 30 with reference to thehousing element 24 will cause the eraser to be projectedfrom the housingelement 24 or drawn into the housing element 24, according to thedirection of rotation.

Also an important feature is that when the eraser is turned into thehousing element 24 to a maximum possible extent, the parts will notstick or bind in such manner as might strip the threads of the screw,but instead the eraser will turn bodily in the eraser holding housingelement and thereby avoid all damage to the device.

The opening 38 in the eraser is at all times sufliciently free toaccommodate the screw without interference therewith. Preferably theopening 38 of the eraser does not extend all the way through, but thisis actually immaterial. The eraser functions in a satisfactory mannereven though it has a central hole therethrough.

It will thus be apparent that when the eraser wears down the housingelement 38 may be turned relative to the housing element 24 to cause itto project from the body a sufiicient amount to enable it to be readilyused. If desired, the eraser then can be retracted into the housingelement 24 or it may be left in the adjusted position.

As clearly shown in Figure 1 of the drawing, the eraser assemblyhereinabove described is so formed that the same fits within the upperend of the body 4 whereby the end of the housing element 24 abuts theupper end of the magazine tube i0, and, while so doing, projects abovethe upper end of the body 4 to provide a portion which may be readilypressed by the thumb to give it a pumping in-and-out movement againstthe action of the spring 46 of the lead propelling mechanism 8. In thisway the eraser assembly acts as a unit as a part of the lead propellingmechanism.

It will be further noted that the eraser assembly thus illustrated iscapable of being reversed in position so that the cap member or housingelement 30 is inside of the pencil and the end of the eraser projectsbeyond the end thereof. This presents the end of the eraser in aposition to be used in the usual manner, but at the same time the eraserassembly is still capable of being used as a part of the lead propellingmechanism. In this position the upper edge 48 of the cap member orhousing element rests on the upper end l2 of the lead magazine tube andtransmits the thrust in exactly the same manner as when the eraserassembly is in the reverse position.

While I have herein described and upon the drawing shown an illustrativeembodiment of the invention, it is to be understood that the in ventionis not limited thereto but may comprehend other consructions,arrangements of parts, details and features without departing from thespirit of the invention.

I claim:

1. A unitary and adjustable eraser assembly in which the eraser iscapable of being advanced and retracted comprising an elongated eraserand a housing therefor, said housing having parts rotatable relative toeach other, and one of said parts having threaded association with saideraser, said eraser assembly having an outside surface of substantiallyuniform cross-section from one end to the other.

2. A unitary eraser assembly comprising a housing of multi-partconstruction provided with means connecting two of said parts to limitmovement of said parts to relative rotational movement, a screw-threadedmember mounted in one of said parts and extending into the other of saidparts, an eraser having a cap disposed within said other of said partsand threadedly engaging said screw-threaded member, and meanscooperating with said cap to hold said eraser against rotationalmovement within said other of said parts whereby said eraser is advancedand retracted in said housing upon relative rotational movement of saidparts.

3. A unitary eraser assembly comprising a screw-threaded member havingan enlarged head, a housing element fixed thereto, a second housingelement associated with said first-named housing, means providing arotatable connection between said second-named housing and said enlargedhead whereby said housing elements are relatively rotatable with oneanother, an eraser having a cap threadedly engaging said screw-threadedmember, and said cap having means frictionally engaging saidsecond-named housing element to hold said eraser against rotationalmovement whereby said eraser is advanced and retracted in said assemblyupon relative rotational movement of said housing elements.

4. A unitary eraser assembly comprising a screw-threaded member havingan enlarged head. a housing element fixed thereto, a second housingelement associated with said first-named housing, said enlarged head andsaid second-named housing element having a cooperating groove andprojection providing a rotational connection between said second-namedhousing and said enlarged head whereby said housings are relativelyrotatable with one another, an eraser having a cap threadedly engagingsaid screw-threaded member, and said cap having means frictionallyengaging said second-named housing element to hold said eraser againstrotational movement whereby said eraser is advanced and retracted insaid assembly upon relative rotational movement of said housingelements.

5. A unitary eraser assembly comprising a screw-threaded member, ahousing element fixed therewith, a second housing element rotatablymounted on said screw-threaded member, an eraser disposed in saidsecond-named housing element and having a bore for receiving saidscrew-threaded member, an eraser cap mounted on said eraser and havingthreaded engagement with said screw-threaded member, and said cap havinga spring finger frictionally engaging said second-named housing elementto prevent rotation of said eraser whereby said eraser may be advancedand retracted upon relative rotation between said housing elements.

6. In a mechanical pencil, the combination of a housing, a unitaryeraser assembly removably associated with said housing, said assemblycomprising a housing connected to the housing for said pencil, ascrew-threaded member fixed to said second-named housing, a sleeverotatably connected to said screw-threaded member and said second-namedhousing, and an eraser having which said screw-threaded member isrotatably mounted, an eraser disposed in said sleeve and embracing saidmember, an eraser cap secured to said eraser and having screw-threadedengagement with said member, and said cap having friction meansengageable with said sleeve to hold said eraser against rotation wherebysaid eraser is advanced and retracted in said sleeve upon relativerotational movement of said sleeve 10 and said first-named cap.

JOHN P. LYNN.

